Catalyst comprising finely divided metals and oxidized metals

ABSTRACT

A process for producing finely divided 20 to 500 angstrom metal particles, metals with oxide coatings or metal oxides using an alkalide or electride in a non-reactive solvent is described. The process produces various forms of the metal depending upon the oxidizability of the metal initially produced by the process. The process is useful for producing catalysts, alloys, colloidal solutions, semi-conductors and the like.

This is a continuation of application(s) Ser. No. 07/950,290 filed onSep. 24, 1992, now abandoned, which is a division of Ser. No.07/522,661, filed May 11, 1990.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to a process and compositions including afinely divided metal, metal oxide coated metal, metal oxide and otheroxidized metal produced by the use of alkalides and electrides to reducea soluble metal salt in an organic solvent. In particular, the presentinvention relates to a process which produces the finely divided metal,metal oxide coated metal or metal oxide or other oxidized metaldepending upon the oxidizability of a metal initially produced by theprocess.

(2) Prior Art

Homogeneous reduction of noble metal salts by mild reducing agents, evenin aqueous solution is well known. Solid alkali metals and suspensionsof alkali metals are also often used as reductants. The use ofhomogeneous strong reducing agents in aprotic solvents to produce finelydivided metals has been limited to reduction by aromatic radical anionsand/or aromatic dianions such as sodium naphthalenide (Rieke, R.,Science 246, 1260-1264 (1989)). Often the reductions are slow and mustbe done at the reflux temperatures of THF. The most common source ofsolvated electrons is found in metal-ammonia and metal-amine solutions.Indeed, these solutions are commonly used in industry and research toreduce organic compounds (Birch reductions). The problem encounteredwith transition metal reductions by metal-ammonia solutions is theformation of metal amides and imides by deprotonation of the solvent.Complex mixtures result from such reactions and one seldom gets thetransition metal itself.

Examples of metal particle production are:

1. Mild reduction of noble metals in the presence of soluble polymers toyield 10-50 Å particles. H. Hirai, Y. Nakao and N. Toshima, J. Macromol.Sci-Chem., A12, 1117 (1978); A13, 727 (1979); H. Hirai, ibid, A13, 633(1979).

2. Zero-valent compounds such as Fe(CO)₅ can be thermally decomposed inpolymers to yield colloidal dispersions of metal. T. W. Smith and D.Wychick, J. Phys. Chem., 84, 1621 (1980).

3. Metal vapor deposition in a solvent matrix can give small metalparticles, M. Kilner, N. Mason, D. B. Lambrick, P. D. Hooker and P. L.Timms, J. Chem. Soc. Chem. Comm., 356 (1987). K. Kimura and S. Bandow,Bull. Chem. Soc. Jpn, 56, 3578 (1983); K. Kimura, ibid, 57, 1683 (1984);60 3093 (1987).

4. Heterogeneous reduction by alkali metals in ethers with or without anaromatic compound present as an electron carrier has been used toprepare metals. R. D. Rieke et al., J. Am. Chem. Soc., 96, 1775 (1974);J. Org. Chem., 40 2253 (1975); ibid 44, 3069 (1979); ibid, 46, 4323(1981) .

Research with alkalides and electrides as described in:

(1) U.S. Pat. No. 4,107,180 to Dye;

(2) J. Am. Chem. Soc. 96, 608-609 (1974);

(3) J. Physical Chem. 79, 3065-3070 (1975);

(4) Angew. Chem. Int. Ed. Engl. 18, 587-598 (1979);

(5) Alkali Metals McGraw-Hill Yearbook of Science and Technology 87-89(1981);

(6) Inorganic Chem., 21, 1966-1970 (1982);

(7) J. Am. Chem. Soc. 105, 6490-6491 (1983);

(8) Chemistry in Britain 20 210-215 (1984);

(9) Progress in Inorganic Chemistry, John Wiley & Sons 32, 327-441(1984);

(10) J. Physical Chem. 88, 3852-3855 (1984);

(11) J. Am. Chem. Soc. 108, 3534-3535 (1986);

(12) J. Am. Chem. Soc. 109, 5561-5563 (1987);

(13) J. Am. Chem. Soc. 101, 7203-7204 (1987);

(14) Valency and Charge Distribution, In Alkalide and Electride Salts,Proceedings of The Robert A. Welch Foundation Conference on ChemicalResearch XXXII Valency, pg 65-91 (1988);

(15) Nature 331, 599-601 (1988);

(16) J. Coord Chem. 18, 121-128 (1988);

(17) J. Am. Chem. Soc. 111, 935-938 (1989);

(18) J. Am. Chem. Soc. 111, 5957-5958 (1989);

(19) Pure & Appl. Chem. 61, 1555-1562 (1989); and

Ann. Rev. Phys. Chem. 38, 271-301 (1987); showed that relativelyconcentrated solutions (>0.1 M in many cases) are obtained which containe_(s) and/or M⁻ in aprotic solvents such as dimethyl ether. Thisresearch provided the possibility to carry out reductions in the absenceof proton sources other than the highly non-acidic --CH₂ -- and --CH₃protons of the solvent and complexant; however, the means foraccomplishing such a reaction was not known.

OBJECTS

It is therefore an object of the present invention to provide a processfor the preparation of a metal, metal with an oxide coating, metal oxideor other oxidized metal depending upon the handling of the reactionproduct and the oxidizability of the metal. Further it is an object ofthe present invention to provide a process which allows the reaction toproceed with an alkalide or electride. These and other objects willbecome increasingly apparent by reference to the following descriptionand the drawings.

IN THE DRAWINGS

FIG. 1 is a schematic view of a photoelectric and auger process ofelectron removal by x-rays on a surface.

FIG. 2 is a graph showing the electron mean free path of an electronreleased by a particular material bombarded by x-rays.

FIG. 3 is a graph showing an x-ray diffraction (XRD) pattern of Auparticles from the reduction of AuCl₃, which was not washed.

FIG. 4 is a graph showing an XRD pattern of Au particles from thereduction of AuCl₃, which was washed with methanol.

FIG. 5 is a graph showing an x-ray photoelectron spectrum (XPS) of Auproduced by reduction of AuCl₃. In all XPS and Auger spectra, M, O, Arepresent peaks due to metal, oxidized metal and compound, respectively.

FIG. 6 is an electron micrograph of Au particles produced by theprocess.

FIG. 7 is a photograph of an electron diffraction pattern of Auparticles.

FIG. 8 is a graph of an XRD pattern of Au on Al₂ O₃.

FIGS. 9A and 9B are electron micrographs of gold particles on Al₂ O₃ ata magnification of 190,000 (550 Angstroms per cm).

FIGS. 10A, 10B and 10C are graphs showing XPS Auger Peak spectra of zincparticles from the reduction of ZnI₂ before and after Argon sputteringto remove an oxide coating.

FIG. 11 is an electron micrograph of Zn aggregation at a magnificationof 100,000 (1000 Angstroms per cm).

FIG. 12 is a graph showing an energy dispersive spectrum (EDS) of Zn/ZnOparticles.

FIGS. 13A, 13B and 13C are graphs showing XPS spectra of Mo from thereduction of MoCl₆.

FIGS. 14A, 14B and 14C are graphs showing XPS Auger Peak spectra of Gafrom the reduction of GaCl₃.

FIGS. 15A and 15B are graphs showing XPS spectra of Sn from thereduction of SnCl₄ before (FIG. 15A) and after exposure to air (FIG.15B).

FIGS. 16A, 16B and 16C are graphs showing XPS spectra of Fe from thereduction of FeCl₃ before and after sputtering in an argon atmosphere.

FIG. 17 is an electron micrograph of Cu and other products from thereduction of CuCl₂ at 100,000 times magnification (1000 Å/cm).

FIG. 18 is a graph showing an EDS spectrum of the reduction of CuCl₂.

FIG. 19 is a graph showing an XPS spectrum of the reduction of TiCl₄.Note that only oxidized titanium is present.

FIG. 20 is an electron micrograph of TiO₂ produced by the process fromTiCl₄ at 100,000 times magnification (1000 Å/cm).

FIG. 21 is a graph showing an XRD pattern of Cu from the reduction ofCuCl₂ washed with methanol.

FIG. 22 is a photograph showing an electron diffraction pattern of Cu.

FIG. 23 is an electron micrograph of Cu particles at 320,000 times (310angstroms per cm).

FIG. 24 is a graph showing an EDS spectrum of Cu particles on a nickelgrid.

FIGS. 25A, 25B and 25C are graphs showing XPS spectra of Cu particlesbefore washing (FIG. 25A) and the presence of CuO after oxidation in air(FIGS. 25B) and after washing with methanol (FIG. 25C).

FIGS. 26A, 26B and 26C are graphs showing the XPS spectra of the productof reduction of TeBr₄ before washing (FIG. 26A), after air oxidation(FIG. 26B) and after a methanol wash (FIG. 26C).

FIGS. 27A, 27B, and 27C are graphs showing the XPS spectra of a Niproduct before air oxidation (FIG. 27A) after being oxidized in air(FIG. 27B) and after washing with methanol (FIG. 27C).

FIGS. 28A, 28B and 28C are graphs showing the XPS spectra of a Sbproduct before washing (FIG. 28A), after washing with methanol (FIG.28B) and after sputtering in argon gas (FIG. 28C).

FIGS. 29A, 29B and 29C are graphs showing the XPS spectra of the Ptproduct after washing with methanol before exposure to air (FIG. 29A)after a brief exposure (16 min) to air (FIG. 29B) and after exposure toair for days (FIG. 29C). The two peaks at the left in FIGS. 28A and 28Bare from the gold-coated cover.

FIG. 30 is an electron micrograph of Pt particles at 320,000 timesmagnification (310Å/cm).

FIG. 31 is a photograph of an electron diffraction pattern of Ptparticles.

FIG. 32 is an electron micrograph of the product of reduction of FeCl₃at 19,000 times magnification (5,000Å/cm).

FIG. 33 is an XRD pattern of Te from the reduction of TeBr₄ afterwashing with methanol.

FIG. 34 is an electron micrograph of Te particles at 140,000 timesmagnification (550Å).

FIG. 35 is a photograph of an electron diffraction pattern of Teparticles.

FIGS. 36A, 36B and 36C are graphs showing the Au XPS spectra from thereduction of a mixture of AuCl₃ and ZnI₂ with AuCl₃ present in excess(FIG. 36A), ZnI₂ present in excess (FIG. 36B) and from the reduction ofAuCl₃ only (FIG. 36C).

FIGS. 37A, 37B are graphs showing the Au XPS spectrum (FIG. 37A) and ZnAuger spectrum (FIG. 37B) of the compound AuZn formed by reduction of amixture of AuCl₃ and ZnI₂.

FIG. 38 is an electron micrograph of AuZn at 100,000 times magnification(1000Å/cm).

FIG. 39 is a photograph of an electron diffraction pattern of AuZnparticles.

FIG. 40 is an electron micrograph of AuCu at 48,000 times magnification(2,000Å/cm).

FIG. 41 is a photograph of an electron diffraction pattern of AuCu.

FIG. 42 is a graph showing the XPS Auger spectrum obtained from theproducts of reduction of a mixture of CuCl₂ and ZnI₂.

FIG. 43 shows an apparatus 10 for producing the finely divided metalparticles.

GENERAL DESCRIPTION

The present invention relates to a process for the production of metalsand oxidized metals by reducing a metal salt with a reducing agent theimprovement which comprises: reducing in a reaction mixture a metal saltwith a reducing agent selected from the group consisting of an electrideand an alkalide in an organic solvent and in the absence of an oxidizingatmosphere to produce the metal in a finely divided form in the solvent.The alkalide or electride may be prepared in advance and dissolved toproduce the solution, or it may be prepared in situ from the alkalimetal(s) and complexant(s).

Further, the present invention relates to a process for the productionof metals and oxidized metals which comprises: reducing in a reactionmixture a metal salt with a reducing agent selected from the groupconsisting of an electride and an alkalide in an organic solvent and inthe absence of an oxidizing atmosphere to produce the metal in a finelydivided form in the solvent; and separating the metal from the solvent,wherein upon separation the metal is oxidized at least at an exposedsurface to an oxidized metal in the presence of oxygen when anoxidizable metal is produced.

The present invention further relates to a reactive metal compositionwhich comprises: a finely divided metal having a particle size betweenabout 20 and 500 Angstroms produced by reducing a metal salt with areducing agent selected from the group consisting of an electride and analkalide; and an organic solvent, wherein the composition is maintainedin the absence of an oxidizing atmosphere.

Finally, the present invention relates to a catalyst which comprises: afinely divided metal with a particle size between about 20 and 500Angstroms produced by reducing a metal salt with a reducing agentselected from the group consisting of an electride and an alkalide toproduce a metal or oxide of the metal upon oxidation of the metal; and anon-reactive support having the metal or oxide of the metal depositedthereon.

The solvated electron, e_(s), is the most powerful reducing agentpossible in a given solvent. Any better reducing agent would react withthe solvent to produce solvated electrons. In addition to itsthermodynamic reducing ability, the solvated electron also usuallyreacts rapidly with metal ions and with simple compounds in which ametal is in a positive oxidation state. Alkali metal anions, M⁻, arenearly as effective as e_(s) and can provide two electrons within asingle encounter.

The electrides and/or alkalides which can be used in the process of thepresent invention include for instance preferably:

(1) Crown Ether Compounds

K⁺(18-crown-6)K⁻, K⁺ (18-crown-6)e⁻ ; general; M⁺ (18-crown-6)_(n) N⁻where M and N are alkali metals and n=1 or 2, (for electrides N⁻ =e⁻).Similar compounds with 15-crown-5 in place of 18-crown-6 or with12-crown-4 or other complexants of the crown-ether class includingmixtures of two different crown-ethers:

2) Cryptands

Na⁺ (Cryptand[2.2.2])Na⁻ or generally M⁺ (Cryptand[m.n.o.])N⁻ includingthe case of N⁻ =e⁻ for electrides:

3) Other Complexants

Any complexant for an alkali metal cation that is not easily reduced bythe trapped electron or alkali metal anions, such as the aza-analogs ofcrown ethers and cryptands, similar cages with other than --CH₂ CH₂ --linkages between the oxygen or nitrogen atoms, simple amines such asmethylamine, ethylamine, ethylenediamine, other di-, tri- andtetra-amines etc. that can form alkalides or electrides of the genericformulas M⁺ (Complexant)mN⁻ or M⁺ (Complexant)_(m) e⁻. M⁺ and N⁻ areselected from sodium, potassium, cesium, rubidium and lithium. Theessential feature is a soluble compound that provides N⁻ or e⁻ whendissolved in a suitable aprotic organic solvent.

The organic solvents which can be used in the present invention areunreactive with the electride or alkalide. Possible solvents aredimethyl ether, diethyl ether tetrahydrofuran, dimethoxy ethane, otherpolyethers. Reducible solvents cannot be used. The reaction temperatureis preferably between -80° C. and 20° C.

The non-oxidizing atmosphere can be provided by various non-reactivegases. Included are nitrogen, argon, helium, and other noble gases.Reaction in vacuo where the vaporized solvent forms the protectiveatmosphere can be performed.

The reaction of all of the soluble metal compounds that contain oxidizedforms of gold (Au), zinc (Zn), molybdenum (Mo), gallium (Ga), tin (Sn),iron (Fe), copper (Cu), titanium (Ti), nickel (Ni), tellurium (Te),antimony (Sb), tungsten (W), vanadium (V), silicon (Si), aluminum (Al)and germanium (Ge), with the electrides or alkalides is generallyessentially complete upon mixing. The presence of a stable blue colorafter addition of excess reductant electride or alkalide indicates thatthe reduction is complete and further that the metal solution is notbeing catalytically decomposed. Generally, a colloidal suspension of themetal (or metal oxide) is first produced as indicated by lightscattering and color, followed by slow aggregation of the colloid to aprecipitate that can be separated by simple centrifugation. The metalswhich can be reduced are in Groups IB to VIIIB and Group IIIA to GroupVIA, including atomic numbers 13, 14, 21-34, 39-52, 57-83, 89 and above.

As an example, a typical reaction scheme between potassium (15-crown 5)₂potasside [K⁺ (15C5)₂ K⁻ ] and tin (IV) chloride (SnCl₄ ) is presumed tofollow the scheme ##STR1## The by-products have been identified by x-raydiffraction (XRD) . Thus, the initial colloid and precipitate containnot only tin metal, but also the other products of reaction. For a metalas inert as tin, a wash with de-oxygenated water leaves the metal with athin layer of oxide or hydroxide. In the case of more active metals suchas Ti, no elemental metal is observed after workup. Thus, even justsolvent removal leaves an oxidized product.

Since an organic complexant such as a crown ether, cryptand or aza-crownis used to prepare the alkalide or electride and provides for ahomogeneous solution, any large-scale use of this methodology wouldrequire recycling of the complexant, a process that is certainlyfeasible. The materials consumed in the reactions are the transitionmetal compound and the alkali metal, neither of which should beprohibitively expensive for a high value-added product.

The following are important features of the process:

(1) The reduction is general, ranging from Al to Te. The onlyrequirement seems to be starting with a compound which is soluble in thesolvent.

(2) It is possible to reduce metal mixtures to form alloys of anydesired composition or intimate mixtures of a less active metal and amore active metal, the latter then forming an oxide, alkoxide or otheroxidized support. Single or mixed metals can be produced on finelydivided support materials, and presumably in the pores of Zeolites or inlayered materials.

(3) Particle size, as determined from the width of x-ray diffraction(XRD) lines and from electron microscopy, ranges from less than about 25Å to several hundred Å.

(4) The process is fast.

(5) The expensive reagents are reusable.

When the metals are produced in situ they can be in a highly reactiveform depending upon the metal. This is particularly true of thetransistion metals. If oxygen is present then a metal oxide can beformed in whole or in part. Further, if a reactive organic or inorganiccompound is present it can react with the metal to form in whole or inpart a derivative oxidized metal compound. Thus alkoxides, esters,ethers, oxyacid salts, chelates and the like can be formed in situ inhigh purity. Further, the metals produced can be used directly tocatalyze reactions such as titanium coupling of esters and ethers. Thepresent invention contemplates such further reactions of the metalsproduced by the process of the present invention.

SPECIFIC DESCRIPTION INSTRUMENTATION

1. X-ray Photoelectron Spectroscopy (XPS or ESCA)

XPS involves the energy analysis of electrons ejected from a surfaceunder bombardment by x-rays. The photoelectron ejection process occurswhen a core level electron absorbs a photon of energy greater than itsbinding energy. When this occurs, the electron is ejected from the atomwith an energy characteristic of the exciting photon and the initialcore level binding energy.

E=H.sup.ν -E_(b)

E is the kinetic energy of the photoelectron

h.sup.ν is the x-ray photon energy

E_(b) is the photoelectron binding energy

When a sample is illuminated by an intense source of photons of a singlewell-defined energy, the resultant photoelectrons can be resolved intoenergy peaks characteristic of the emitting atoms. In addition to thephotoelectron emitted in the photoelectric process, Auger electrons areemitted due to relaxation of the energetic ions that remain afterphotoemission. Auger electron emission occurs about 10⁻¹⁴ sec. after thephotoelectric event. Thus, photoionization often leads to two emittedelectrons, a photoelectron and an Auger electron as shown in FIG. 1.

The path length of the photons is of the order of micrometers, but thatof the electrons is of the order of ten Angstroms. Thus, whileionization occurs to a depth of a few micrometers, only those electronsthat originate within tens of Angstroms of the solid surface can leavethe surface without energy loss. It is these electrons that produce thepeaks in the spectra and are most useful. Those that undergo lossprocesses before emerging contribute to the background. Experimentaldata on the mean free paths of electrons in various materials are shownin FIG. 2.

The XPS measurements reported here were performed with a Perkin ElmerPHI 5400 ESCA/XPS™ spectrometer (Eden Prairie, Minn.). UnmonochromatizedMgK alpha x-ray sources were used at 15 KV and 300 W. The work functionof the instrument was calibrated by measuring the binding energy of Au4f_(7/2) at 84.0±0.1 eV. During experiments the pressure inside theanalyzer chamber was about 10⁻⁸ torr. Ion bombardment to etch awaysample surfaces was carried out with an argon ion gun. Bothphotoelectron and AUGER peaks could be obtained by XPS.

2. X-Ray Diffraction Powder Patterns (XRD)

The mean dimension, D_(hkl), along the Miller index hkl of thecrystallites of a powder as related to the pure x-ray diffraction linebroadening was calculated by Scherrer's equation

    Dhk.sub.1 =0.9λ/βcos θ

in which

λ is the wavelength of the x-ray

β is the angular width at half-maximum intensity

θ is the Bragg angle

A Rigaku™ (Rotaflex model; Danvers, Me.) x-ray powder diffractometerusing a rotating anode and monitored with a Microvax™ computer was used.Data were recorded at 45 KV and 80 mA with the CuKalpha radiation.

3. Transmission Electron Microscopy (TEM), Energy Dispersive Spectra(EDS) and Electron Diffraction Patterns

All micrographs were taken with a JEOL 100 CXII™ Transmission ElectronMicroscope (Peabody, Me.) using 100 KV accelerating voltage. EnergyDispersive Spectra (EDS) were recorded with a Link Systems AN 10000™(Redwood City, Calif.). The Electron Microscope was also used to obtainthe Electron Diffraction Patterns.

SAMPLE PREPARATION

All the metal salts were purchased in the highest available purity.Liquid samples were TiCl₄ (99.995+%), GeCl₄ (99.999%), SiCl₄ (99.999%),SbCl₄ (99%) and SnCl₄ (99.999%). Solid samples were CuCl₂ (99.9999%),GaCl₃ (99.99%) , ZnI₂ (99.99%) , AlCl₃ (99.9%) , MoCl₅ (99.99%), FeCl₃(98%) and AuCl₃. A 0.25 mm thick 99.99% indium foil was used to mountthe samples for XPS and XRD studies.

As shown in FIG. 43, a few milligrams of the desired compound A wereadded to one side of an evacuated H-cell 10 made of borosilicate glassas shown in FIG. 43 with a medium frit 11 in a He-filled dry box (notshown). The cell 10 was fitted with Kontes™ (Morton Grove, Ill.) vacuumvalves 12 and 13. Vacuum was drawn through tubes 14 or 15. Enoughalkalide or electride B was added to the other side of the H-cell 10 ina nitrogen-filled glove bag. A liquid nitrogen bath was used to cool thecell 10 to prevent decomposition of the alkalide or electride B.Prepurified dimethyl ether was introduced as the solvent into thealkalide or electride under vacuum after pumping out the helium gas toabout 10⁻⁵ torr while the cell was kept in a -80° to 20° C., preferably-50° C. isopropanol bath.

The blue solution of the alkalide or electride was poured through thefrit 11 to react with the solution of the metal compound A to be reducedafter both solids had been completely dissolved in dimethyl ether. Thereaction was complete immediately after the addition of alkalide orelectride as indicated by fading of the blue color. A slight excess ofalkalide or electride was added until the blue color no longerdisappeared to make sure that the reaction was complete. Differentcolors of various colloids were formed at the same time. Then thedimethyl ether was distilled out under vacuum.

The products were removed from the walls of the H-cell 10 and mounted onan indium foil in the He dry box. A vacuum transfer apparatus was usedto carry the sample from the dry box to the XPS chamber without exposingthe sample to the air. In some cases deionized and degassed distilledwater or methanol was used to wash away the by-products. Washing wasperformed by centrifugation to separate the undissolved metallicparticles from the water or methanol soluble by-products. XRD patternswere recorded by placing the precipitate on indium foil either with orwithout washing. A drop of washed suspension was put on the TEM grid orthe grid was dipped into the suspension and allowed to dry in the air,after which TEM micrographs, EDS, and electron diffraction patterns weremade.

EXAMPLE 1 Gold

Gold Chloride, AuCl₃, was reduced by the alkalide, K⁺ (15C5)₂ K⁻, toproduce small metallic gold particles. Note that K⁺ (15C5)₂ K⁻ is thenominal composition used. Other studies show that both K⁺ (15C5)₂ K⁻ andK⁺ (15C5)₂ e⁻ are present unless the compound is carefullyrecrystallized. The products were fully characterized by x-ray powderdiffraction, electron diffraction and x-ray photoelectron spectroscopy.Only metallic gold peaks were detected by XRD from the precipitatesafter washing away the by-products, K⁺ (15C5)₂ Cl⁻ and KCl. The meanparticle size of the strongest peak of Au (III) from the x-ray linebroadening, as shown in FIG. 3, is about 100 Å before washing. FIG. 4shows that the mean particle size from a different run was about 70 Åafter two washes with water.

The small black metallic Au particles were also characterized by XPS andonly the 4f_(7/2) peak at 83.9 eV and the 4f^(5/2) peak at 98.7 eVappear on the XPS spectra of FIG. 5, showing that these particles aremetallic gold. The micrograph of FIG. 6 with a magnification of 320,000agrees well with the particle size of about 100 Å as measured by x-rayline broadening of gold produced in the same run. A selected areaelectron diffraction pattern was also taken from the same area shown inthe micrograph of FIG. 6. The ring pattern of FIG. 7 matches all of thed-spacings of metallic gold.

It was also possible to do the reduction in the presence of finelydivided alumina (Al₂ O₃) with a specific surface area of 158 m² /g. Onegram of Al₂ O₃ and a few milligrams of AuCl₃ were combined in one arm ofthe H-cell, reduction was conducted as before. The final purple productwas confirmed to be Au deposited on Al₂ O₃ by both XRD and TEM. The meanAu particle size shown in FIG. 8 is about 50 Å. From the TEM micrographshown in FIGS. 9A and 9B with a magnification of 190,000, the Auparticles (black spots) are seen to be deposited uniformly on thesurface of Al₂ O₃.

EXAMPLE 2 Zinc

ZnI₂ was reduced by K⁺ (15C5)₂ K⁻ (with possibly some K⁺ (15C5)₂ e⁻) indimethyl ether. Neither metallic zinc nor the zinc oxide peak wasdetected by XRD studies of the washed precipitate which means that theparticle size of the product is so small that the powder peak cannot beobserved. This corresponds to a mean particle diameter of less than 25Å. The XPS spectra of FIG. 10 show that the L₃ M₄₅ M₄₅ AUGER peaks ofboth the metal and the oxide appear. (A) is the spectrum of the reactionproducts, while (B) and (C) are the results after 2 and 5 minutessputtering by argon ions. As the surface oxide layer is sputtered off,the metal peak increases and the oxide peak decreases. The micrograph ofFIG. 11 shows the aggregation of the zinc particles. Only zinc peaksappear in the EDS spectrum of FIG. 12 which shows that these particlesare either zinc or zinc oxide (note that oxygen cannot be detected byour EDS system).

EXAMPLE 3 Molybdenum

MoCl₆ was reduced by K⁺ (15C5)₂ K⁻ in dimethyl ether. Again bothmetallic and oxide 3d_(5/2) and 3d_(3/2) XPS peaks appear in FIG. 13.The metal peak increases and the oxide peak decreases after 10 and 20minutes of argon sputtering as shown in FIGS. 13 (B) and (C)respectively.

EXAMPLE 4 Gallium

GaCl₃ was reduced by K⁺ (15C5)₂ K⁻ in dimethyl ether. FIGS. 14 (A) and(B) show the sputtering effect on the metal and oxide L₃ M₄₅ M₄₅ Augerpeaks before and after two minutes. FIG. 14B and FIG. 14C were taken atthe same time after two minutes of sputtering. The relative intensity ofmetal to oxide in FIG. 14B and FIG. 14C is greater than that in FIG.14A, so we know that oxide exists only on a few surface layers.

EXAMPLE 5 Tin

SnCl₄ was reduced by K⁺ (15C5)₂ K⁻ in dimethyl ether. FIG. 15A showsthat the 3d_(5/2) and 3d_(3/2) peaks of both the metal and the oxide arepresent. The metal peaks decreased dramatically as shown in FIG. 15Bafter the sample had been exposed for just a few seconds to the air.This shows how easily the small tin particles are oxidized.

EXAMPLE 6 Iron

FeCl₃ was reduced by K⁺ (15C5)₂ K⁻ in dimethyl ether. FIG. 16A shows theXPS results of the 2p_(3/2) and 2p_(1/2) peaks of both the metal and theoxide before sputtering. FIGS. 16B and FIG. 16C show the results after 5and 15 minutes of sputtering, respectively. Again, these resultsindicate that metallic iron is produced by reduction but that thesurface layer is oxidized.

EXAMPLE 7 Copper

CuCl₂ was reduced by K+(15C5)₂ K⁻ in THF. The XRD spectrum of theproduct was run after washing away the by-products, KCl and K⁺ (15C5)₂Cl⁻, and again no peak was observed in the XRD, which indicates thateither the particle size was very small or the intensity was too low toobserve. The micrograph shown in FIG. 17 displays the aggregation of theproduct. The EDS spectrum of FIG. 18 for these particles shows onlycopper peaks and background peaks from the nickel grid.

EXAMPLE 8 Titanium

TiCl₄ was reduced by K⁺ (15C5)₂ K⁻ in dimethyl ether. Only the 2p_(3/2)and 2p_(1/2) titanium oxide peaks were observed in the XPS spectrumshown in FIG. 19. The particle size from the micrograph of FIG. 20 (at400Å/cm) is estimated to be about 20 to 40 Å. Again EDS spectroscopydetected only titanium peaks.

EXAMPLE 9 Silicon, Aluminum, Vanadium and Tungsten

SiCl₄, AlCl₃, VCl₃ and WCl₆ were also reduced by K⁺ (15C5)₂ K⁻ indimethyl ether. The blue color of the alkalide disappeared in all casesand precipitates formed but the products have not yet beencharacterized. The products are believed to be metals and/or oxides.

EXAMPLE 10 Copper Using a Different Alkalide

Copper Chloride, CuCl₂, was reduced by the alkalide, Rb⁺ (15C5)₂ Rb⁻, toproduce small metallic copper particles. These were fully characterizedby x-ray powder diffraction (XRD) , electron diffraction (ED) , andx-ray photoelectron spectroscopy (-XPS). Only metallic copper peaks weredetected by XRD from the precipitates after washing away theby-products, Rb(15C5)₂ Cl and RbCl. The mean particle size of thestrongest peak of Cu(111) from the XRD line broadening, as shown in FIG.21, is about 57 A after washing by methanol.

FIG. 22 shows the unique electron diffraction pattern of metallic copperlines (111), (200), (220), (311) from inner to outside rings. Themicrograph of FIG. 23 with a magnification of 320,000 agrees well withthe particle size of 57 A from the XRD line broadening of metallic Cuproduct in the same run. These particles were also characterized byenergy dispersive spectroscopy as shown in FIG. 24. Only Cu peaks appearon Ni grid.

The small Cu particles were also characterized by XPS and only the peaksof 2p_(3/2) at 932.6 eV and 2p_(1/2) at 952.4 eV appear on FIG. 25Abefore washing and FIG. 25C after washing away by-products by methanol.FIG. 25B shows that a small amount of CuO is present on the Cu surfaceafter standing in air for 24 hours.

EXAMPLE 11 Tellurium

TeBr₄ was reduced by K⁺ (15C5)₂ e⁻ in dimethyl ether. FIG. 26A shows theXPS results of the 3d_(5/2) and 3d_(3/2) peaks of metallic Te beforewashing. After oxidizing these products in the air 3 minutes, the oxidepeaks are larger than metal peaks as shown in FIG. 26B. These particleswere partially oxidized after washing by methanol as shown in FIG. 26C.Clean metallic Te peaks were observed in another methanol washedproduct. Electron diffraction studies showed that the particles wereelemental tellurium.

EXAMPLE 12 Nickel

By adding triethyl phosphine to increase the solubility, NiBr₂ wasreduced by K⁺ (15C5)₂ K⁻ in dimethyl ether. The products were kept in anH-cell under vacuum 4 days and analyzed by XPS. FIG. 27A shows metallicNi peaks only. Small amount of NiO peaks appear when these particleswere oxidized in the air 24 hours, but all Ni particles were oxidizedafter washing by methanol as shown in FIGS. 27B and 27C.

EXAMPLE 13 Antimony

SbCl₅ was reduced by K⁺ (15C5)₂ K⁻ in dimethyl ether. Both metallic andoxide 3d_(5/2) and 3d_(3/2) XPS peaks appear in FIGS. 28A and 28B beforeand after washing with methanol. The washed products were sputtered by14 mpA Ar ion 20 minutes. The result in FIG. 28C shows that only a smallamount of oxide is left after sputtering.

EXAMPLE 14 Reducing Agents

Six (6) alkalides and 1 electride were used as reducing agentsincluding: K⁺ (18C6)Na⁻, Cs⁺ (18C6)₂ Na⁻, Cs⁺ (15C5)₂ Na⁻, Rb⁺ (15C5)₂Na⁻, K⁺ (15C5)₂ ^(K-), Rb⁺ (15C5)₂ Rb⁻ and K⁺ (15C5)₂ e⁻. There was nodifference in the reducing ability between them as the blue colors ofalkalide or electride disappeared immediately upon reaction.

As can be seen from the foregoing examples, four elements have beenproduced by alkalide or electride without oxide on the metal surfaceincluding: Au, Te, Cu and Ni. Six elements, Fe, Zn, Ga, Mo, Sn and Sb,have oxides on their surfaces by XPS. AlCl₃, SiCl₄, VCl₃, GeCl₄ and WCl₆can react with alkalide or electride but the precipitates have not yetbeen characterized. Oxidized titanium (TiO₂ or other product) which hasbeen characterized by XPS is the only product from the reduction ofTiCl₄ by this method.

FIGS. 29 to 42 show various metals, compounds and compositions which areproduced by the method of the present invention.

The following represent some possible applications for the finelydivided metals, metals with oxide coatings and metal oxides:

1) Precipitation of a single metal or several metals on a support forcatalytic purposes. Noble metal particles can be deposited on an oxidesupport such as Al₂ O₃. Perhaps most important here would be thoseapplications that require intimate mixtures of two or more metals onsuch a support. More reactive metals and alloys can also be prepared onsuch supports but there would be surface or complete oxidation. Ofcourse, there is no reason that the support could not have other forms,such as sintered metal oxides, "honeycomb" structures, and the like.

2) Preparation of extremely high surface area metal on metal oxidecatalysts by co-precipitation of a noble metal and an active metal. Forexample, Pt and Ti could be co-precipitated to obtain Pt metal in highconcentrations on extremely small TiO₂ particles. The number of possiblecombinations is enormous and include alkoxide supports (with an alcoholwash) or other supports, depending on workup conditions.

3) Ceramic precursors can be prepared by appropriate mixtures of activemetals which could be fired to a final ceramic.

4) Difficult-to-produce new alloys can be prepared by coprecipitation oftwo or more metals. The advantage of low temperature processing ispossible.

5) Colloidal metal solutions should be readily produced by the processof the present invention if one takes steps to prevent aggregation suchas by adding dispersants.

6) Small semiconductor particles such as GaAs can be produced byreducing a mixture of Ga and As compounds. A solid-state reaction insuch small particles could occur to yield the stable III-V compound. Themain advantages of the process of the present invention are its wideapplicability to many different compounds, the fact that reductionoccurs rapidly from a homogeneous solution, and the low temperatures atwhich metallic particles can be produced. The process of the presentinvention points the way to entirely new families of catalysts andalloys which cannot be prepared in any other way.

It is intended that the foregoing description be only illustrative ofthe present invention and that the present invention be limited only bythe hereinafter appended claims.

We claim:
 1. A catalyst which comprises:(a) finely divided gold with aparticle size between about 20 and 500 Angstroms produced by reducing agold salt with a reducing agent selected from the group consisting of anelectride and an alkalide having a formula selected from the groupconsisting of M⁺ (Complexant)N⁻ and M⁺ (Complexant)_(m) e⁻ wherein M⁺and N⁻ are selected from the group consisting of sodium, potassium,cesium, rubidium and lithium in an organic solvent and under anonoxidizing atmosphere to produce the gold; and (b) an alumina supporthaving the gold deposited thereon wherein the support with the gold canbe used as the catalyst.
 2. The method of claim 1 wherein the alkalideis K⁺ (15C5) ₂ K⁻.
 3. The method of claim 1 wherein the alkalide is Rb⁺(15C5) ₂ Rb⁻.
 4. A catalyst which comprises:(a) finely divided platinumwith a particle size between about 20 and 500 Angstroms produced byreducing a platinum salt with a reducing agent selected from the groupconsisting of an electride and an alkalide having a formula selectedfrom the group consisting of M⁺ (Complexant)N⁻ and M⁺ (Complexant)_(m)e⁻ wherein M⁺ and N⁻ are selected from the group consisting of sodium,potassium, cesium, rubidium and lithium in an organic solvent and undera non-oxidizing atmosphere to produce the platinum; and (b) a titaniumdioxide support having the platinum deposited thereon wherein thesupport with the platinum can be used as the catalyst.
 5. The catalystof claim 4 wherein the alkalide is K⁺ (15C5) ₂ K⁻.
 6. The catalyst ofclaim 4 wherein the alkalide is Rb⁺ (15C5) ₂ Rb⁻.